This invention relates generally to improvements in hydraulic actuation systems for aircraft control surfaces and more particularly to an actuation system having two offset pivot points.
Numerous devices have been proposed for the actuation of aircraft control surfaces and hydraulic, pneumatic and mechanical actuating devices are well known. In aircraft having low thickness to chord ratio (thin high speed wings with sharper leading and trailing edges) little room is left to house the actuators and control arms for the aerodynamic movable surfaces. This is true for low aspect wings, that is, short wing span relative to wing chord length.
Most modern aircraft now, however, utilize high aspect ratio wings which are large span to chord length. As the width (chord) of the wing is decreased and thickness is reduced for high speed, it becomes increasingly important to utilize all available wing space for fuel storage, thus reducing the amount of space available for the control surface actuation system. Examples of multi-cylinder hydraulic actuation systems can be found in U.S. Pat. Nos. 2,861,758, 2,863,321, 2,899,152, and 2,972,898. U.S. Patent Nos. 4,395,007, 4,544,118, and 4,773,620 are representative of single cylinder hydraulic actuation systems.
There exists, therefore, a significant need for an improved hydraulic actuation system which minimizes the space required therefor. The present invention fulfills this need and provides further related advantages.